Tape libraries have historically been the primary storage devices for amassed digital data. This has been due in part because of the tape libraries' ability to store considerably large amounts of data in a cost-efficient and data-stable manner. Other types of storage systems containing alternative media such as disc drives, optical storage systems and flash memory, however, are gaining momentum as a consequence of advancements in random storage access technology and relative cost improvements. These alternative storage systems take advantage of random access memory storage functionality which can dramatically speed up data transfer between a host and storage system.
Generally, a host computer is adapted to store, retrieve, and manipulate data with compatible storage systems comprising compatible storage devices operable to manage data on compatible storage media. Such storage operations are typically accomplished by using a specific data storage protocol compatible with a specific type of storage system. For example, if a host computer is adapted to store data in a tape library, communication and data transfer between the tape library and the host is typically accomplished by a tape library protocol. Some storage systems leveraging disc drive storage technology are configured to emulate a tape library and store data received from the host as if they were a tape library using the tape library protocol. Such advances are evident in a Virtual Tape Library (VTL) which is a leading alternative to the traditional tape library.
Though systems like VTLs have virtues such as improved data transfer speed and redundant storage backup using RAID, they are often limited to a fixed storage capacity, unlike the tape libraries which can use a mobile, restorable supply of tape cassettes. In addition, storage systems, such as the VTL, are further restricted to a specific data storage protocols for storing data.
In an effort to provide an improvement in versatility for storing and retrieving data with a host computer coupled with replenishable storage capacity, both methods and apparatus are proposed herein. It is to innovations related to this subject matter that the claimed invention is generally directed.